The present invention is in the field of enzyme proteins that are related to the metalloprotease enzyme subfamily, recombinant DNA molecules, and protein production. The present invention specifically provides novel peptides and proteins and nucleic acid molecules encoding such peptide and protein molecules, all of which are useful in the development of human therapeutics and diagnostic compositions and methods.
Many human enzymes serve as targets for the action of pharmaceutically active compounds. Several classes of human enzymes that serve as such targets include helicase, steroid esterase and sulfatase, convertase, synthase, dehydrogenase, monoxygenase, transferase, kinase, glutanase, decarboxylase, isomerase and reductase. It is therefore important in developing new pharmaceutical compounds to identify target enzyme proteins that can be put into high-throughput screening formats. The present invention advances the state of the art by providing novel human drug target enzymes related to the metalloprotease subfamily.
Endothelin-Converting Enzymes
The novel human protein, and encoding gene, provided by the present invention is related to the family of metalloprotease enzymes (also referred to as the peptidase family M13, zinc metalloprotease family, and the neprilysin family) in general and shows a high degree of similarity to the endothelin-converting enzyme subfamily of metalloproteases. Furthermore, the protein of the present invention may be a novel isoform of the gene provided in Genbank gi7662200 (see the amino acid sequence alignment in FIG. 2).
Endothelin-coverting enzymes (ECE) are membrane-bound metalloproteases that catalyze the proteolytic activation of endothelins, which are potent vasoactive peptides. Endothelins are produced from biologically inactive intermediates known as big endothelins by ECE-catalyzed proteolytic processing. ECE function in secretory pathways as well as on the cell surface. ECE-1 and ECE-2 have been characterized. ECE-2 is structurally related to ECE-1, neural endopeptidase 24.11, and human Kell blood group protein. ECE-1 and ECE-2 are both inhibited by phosphoramidon. ECE-1 is most active at neutral pH, whereas an acidic pH is optimum for ECE-2. It is though that ECE-2 converts endogenously synthesized big endothelin-1 to mature endothelin-1 at the acidic environement of the trans-Golgi network (Emoto et al., J Biol Chem 1995 Jun 23;270(25):15262-8).
Metalloproteases
The metalloproteases may be one of the older classes of proteinases and are found in bacteria, fungi as well as in higher organisms. They differ widely in their sequences and their structures but the great majority of enzymes contain a zinc atom which is catalytically active. In some cases, zinc may be replaced by another metal such as cobalt or nickel without loss of the activity. Bacterial thermolysin has been well characterized and its crystallographic structure indicates that zinc is bound by two histidines and one glutamic acid. Many enzymes contain the sequence HEXXH, which provides two histidine ligands for the zinc whereas the third ligand is either a glutamic acid (thermolysin, neprilysin, alanyl aminopeptidase) or a histidine (astacin). Other families exhibit a distinct mode of binding of the Zn atom. The catalytic mechanism leads to the formation of a non covalent tetrahedral intermediate after the attack of a zinc-bound water molecule on the carbonyl group of the scissile bond. This intermediate is further decomposed by transfer of the glutamic acid proton to the leaving group.
Metalloproteases contain a catalytic zinc metal center which participates in the hydrolysis of the peptide backbone (reviewed in Power and Harper, in Protease Inhibitors, A. J. Barrett and G. Salversen (eds.) Elsevier, Amsterdam, 1986, p. 219). The active zinc center differentiates some of these proteases from calpains and trypsins whose activities are dependent upon the presence of calcium. Examples of metalloproteases include carboxypeptidase A, carboxypeptidase B, and thermolysin.
Metalloproteases have been isolated from a number of procaryotic and eucaryotic sources, e.g. Bacillus subtilis (McConn et al., 1964, J. Biol. Chem. 239:3706); Bacillus megaterium; Serratia (Miyata et al., 1971, Agr. Biol. Chem. 35:460); Clostridium bifermentans (MacFarlane et al., 1992, App. Environ. Microbiol. 58:1195-1200), Legionella pneumophila (Moffat et al., 1994, Infection and Immunity 62:751-3). In particular, acidic metalloproteases have been isolated from broad-banded copperhead venoms (Johnson and Ownby, 1993, Int. J. Biochem. 25:267-278), rattlesnake venoms (Chlou et al., 1992, Biochem. Biophys. Res. Commun. 187:389-396) and articular cartilage (Treadwell et al., 1986, Arch. Biochem. Biophys. 251:715-723). Neutral metalloproteases, specifically those having optimal activity at neutral pH have, for example, been isolated from Aspergillus sojae (Sekine, 1973, Agric. Biol. Chem. 37:1945-1952). Neutral metalloproteases obtained from Aspergillus have been classified into two groups, npI and npII (Sekine, 1972, Agric. Biol. Chem. 36:207-216). So far, success in obtaining amino acid sequence information from these fungal neutral metalloproteases has been limited. An npI metalloprotease isolated from Aspergillus oryzae has been cloned based on amino acid sequence presented in the literature (Tatsumi et al., 1991, Mol. Gen. Genet. 228:97-103). However, to date, no npI fungal metalloprotease has been cloned or sequenced. Alkaline metalloproteases, for example, have been isolated from Pseudomonas aeruginosa (Baumann et al., 1993, EMBO J 12:3357-3364) and the insect pathogen Xenorhabdus luminescens (Schmidt et al., 1998, Appl. Environ. Microbiol. 54:2793-2797).
Metalloproteases have been devided into several distinct families based primarily on activity and sturcture: 1) water nucleophile; water bound by single zinc ion ligated to two His (within the motif HEXXH) and Glu, His or Asp; 2) water nucleophile; water bound by single zinc ion ligated to His, Glu (within the motif HXXE) and His; 3) water nucleophile; water bound by single zinc ion ligated to His, Asp and His; 4) Water nucleophile; water bound by single zinc ion ligated to two His (within the motif HXXEH) and Glu and 5) water nucleophile; water bound by two zinc ions ligated by Lys, Asp, Asp, Asp, Glu.
Examples of members of the metalloproteinase family include, but are not limited to, membrane alanyl aminopeptidase (Homo sapiens), germinal peptidyl-dipeptidase A (Homo sapiens), thimet oligopeptidase (Rattus norvegicus), oligopeptidase F (Lactococcus lactis), mycolysin (Streptomyces cacaoi), immune inhibitor A (Bacillus thuringiensis), snapalysin (Streptomyces lividans), leishmanolysin (Leishmania major), microbial collagenase (Vibrio alginolyticus), microbial collagenase, class I (Clostridium perfringens), collagenase 1 (Homo sapiens), serralysin (Serratia marcescens), fragilysin (Bacteroides fragilis), gametolysin (Chlamydomonas reinhardtii), astacin (Astacus fluviatilis), adamalysin (Crotalus adamanteus), ADAM 10 (Bos taurus), neprilysin (Homo sapiens), carboxypeptidase A (Homo sapiens), carboxypeptidase E (Bos taurus), gamma-D-glutamyl-(L)-meso-diaminopimelate peptidase I (Bacillus sphaericus), vanY D-Ala-D-Ala carboxypeptidase (Enterococcus faecium), endolysin (bacteriophage A118), pitrilysin (Escherichia coli), mitochondrial processing peptidase (Saccharomyces cerevisiae), leucyl aminopeptidase (Bos taurus), aminopeptidase I (Saccharomyces cerevisiae), membrane dipeptidase (Homo sapiens), glutamate carboxypeptidase (Pseudomonas sp.), Gly-X carboxypeptidase (Saccharomyces cerevisiae), O-sialoglycoprotein endopeptidase (Pasteurella haemolytica), beta-lytic metalloendopeptidase (Achromobacter lyticus), methionyl aminopeptidase I (Escherichia coli), X-Pro aminopeptidase (Escherichia coli), X-His dipeptidase (Escherichia coli), IgA1-specific metalloendopeptidase (Streptococcus sanguis), tentoxilysin (Clostridium tetani), leucyl aminopeptidase (Vibrio proteolyticus), aminopeptidase (Streptomyces griseus), LAP aminopeptidase (Escherichia coli), aminopeptidase T (Thermus aquaticus), hyicolysin (Staphylococcus hyicus), carboxypeptidase Taq (Thermus aquaticus), anthrax lethal factor (Bacillus anthracis), penicillolysin (Penicillium citrinum), fungalysin (Aspergillus fumigatus), lysostaphin (Staphylococcus simulans), beta-aspartyl dipeptidase (Escherichia coli), carboxypeptidase Ss1 (Sulfolobus solfataricus), FtsH endopeptidase (Escherichia coli), glutamyl aminopeptidase (Lactococcus lactis), cytophagalysin (Cytophaga sp.), metalloendopeptidase (vaccinia virus), VanX D-Ala-D-Ala dipeptidase (Enterococcus faecium), Ste24p endopeptidase (Saccharomyces cerevisiae), dipeptidyl-peptidase III (Rattus norvegicus), S2P protease (Homo sapiens), sporulation factor SpoIVFB (Bacillus subtilis), and HYBD endopeptidase (Escherichia coli).
Metalloproteases have been found to have a number of uses. For example, there is strong evidence that a metalloprotease is involved in the in vivo proteolytic processing of the vasoconstrictor, endothelin-1. Rat metalloprotease has been found to be involved in peptide hormone processing. One important subfamily of the metalloproteases are the matrix metalloproteases.
A number of diseases are thought to be mediated by excess or undesired metalloprotease activity or by an imbalance in the ratio of the various members of the protease family of proteins. These include: a) osteoarthritis (Woessner, et al., J. Biol.Chem. 259(6), 3633, 1984; Phadke, et al., J. Rheumatol. 10, 852, 1983), b) rheumatoid arthritis (Mullins, et al., Biochim. Biophys. Acta 695, 117, 1983; Woolley, et al., Arthritis Rheum. 20, 1231, 1977; Gravallese, et al., Arthritis Rheum. 34, 1076, 1991), c) septic arthritis (Williams, et. al., Arthritis Rheum. 33, 533, 1990), d) tumor metastasis (Reich, et al., Cancer Res. 48, 3307, 1988, and Matrisian, et al., Proc. Nat""l. Acad. Sci., USA 83, 9413, 1986), e) periodontal diseases (Overall, et al., J. Periodontal Res. 22, 81, 1987), f) corneal ulceration (Burns, et al., Invest. Opthalmol. Vis. Sci. 30, 1569, 1989), g) proteinuria (Baricos, et al., Biochem. J. 254, 609, 1988), h) coronary thrombosis from atherosclerotic plaque rupture (Henney, et al., Proc. Nat""l. Acad. Sci., USA 88, 8154-8158, 1991), i) aneurysmal aortic disease (Vine, et al., Clin. Sci. 81, 233, 1991), j) birth control (Woessner, et al., Steroids 54, 491, 1989), k) dystrophobic epidermolysis bullosa (Kronberger, et al., J. Invest. Dermatol. 79, 208, 1982), and 1) degenerative cartilage loss following traumatic joint injury, m) conditions leading to inflammatory responses, osteopenias mediated by MMP activity, n) tempero mandibular joint disease, o) demyelating diseases of the nervous system (Chantry, et al., J. Neurochem. 50, 688, 1988).
Proteases and Cancer
Proteases are critical elements at several stages in the progression of metastatic cancer. In this process, the proteolytic degradation of structural protein in the basal membrane allows for expansion of a tumor in the primary site, evasion from this site as well as homing and invasion in distant, secondary sites. Also, tumor induced angiogenesis is required for tumor growth and is dependent on proteolytic tissue remodeling. Transfection experiments with various types of proteases have shown that the matrix metalloproteases play a dominant role in these processes in particular gelatinases A and B (MMP-2 and MMP-9, respectively). For an overview of this field see Mullins, et al., Biochim. Biophys. Acta 695, 177, 1983; Ray, et al., Eur. Respir. J. 7, 2062, 1994; Birkedal-Hansen, et al., Crit. Rev. Oral Biol. Med. 4, 197, 1993.
Furthermore, it was demonstrated that inhibition of degradation of extracellular matrix by the native matrix metalloprotease inhibitor TIMP-2 (a protein) arrests cancer growth (DeClerck, et al., Cancer Res. 52, 701, 1992) and that TIMP-2 inhibits tumor-induced angiogenesis in experimental systems (Moses, et al. Science 248, 1408, 1990). For a review, see DeClerck, et al., Ann. N. Y. Acad. Sci. 732, 222, 1994. It was further demonstrated that the synthetic matrix metalloprotease inhibitor batimastat when given intraperitoneally inhibits human colon tumor growth and spread in an orthotopic model in nude mice (Wang, et al. Cancer Res. 54, 4726, 1994) and prolongs the survival of mice bearing human ovarian carcinoma xenografts (Davies, et. al., Cancer Res. 53, 2087, 1993). The use of this and related compounds has been described in Brown, et al., WO-9321942 A2.
There are several patents and patent applications claiming the use of metalloprotease inhibitors for the retardation of metastatic cancer, promoting tumor regression, inhibiting cancer cell proliferation, slowing or preventing cartilage loss associated with osteoarthritis or for treatment of other diseases as noted above (e.g. Levy, et al., WO-9519965 A1; Beckett, et al., WO-9519956 A1; Beckett, et al., WO-9519957 A1; Beckett, et al., WO-9519961 A1; Brown, et al., WO-9321942 A2; Crimmin, et al., WO-9421625 A1; Dickens, et al., U.S. Pat. No. 4,599,361; Hughes, et al., U.S. Pat. No. 5,190,937; Broadhurst, et al., EP 574758 A1; Broadhurst, et al., EP 276436; and Myers, et al., EP 520573 A1.
Enzyme proteins, particularly members of the metalloprotease enzyme subfamily, are a major target for drug action and development. Accordingly, it is valuable to the field of pharmaceutical development to identify and characterize previously unknown members of this subfamily of enzyme proteins. The present invention advances the state of the art by providing previously unidentified human enzyme proteins, and the polynucleotides encoding them, that have homology to members of the metalloprotease enzyme subfamily. These novel compositions are useful in the diagnosis, prevention and treatment of biological processes associated with human diseases.
The present invention is based in part on the identification of amino acid sequences of human enzyme peptides and proteins that are related to the metalloprotease enzyme subfamily, as well as allelic variants and other mammalian orthologs thereof. These unique peptide sequences, and nucleic acid sequences that encode these peptides, can be used as models for the development of human therapeutic targets, aid in the identification of therapeutic proteins, and serve as targets for the development of human therapeutic agents that modulate enzyme activity in cells and tissues that express the enzyme. Experimental data as provided in FIG. 1 indicates expression in humans in the lung, amygdala, adrenal gland, hippocampus, and fetus.